Work planned for the coming year will concentrate more heavily on studies of the ultrastructural correlates of ion and fluid transport and macromolecule secretion in epithelial cells which are possible candidates for the type of cell affected by the genetic defect in Cystic Fibrosis. Attempts at identifying an abnormal cell or cell organelle in patients with CF will entail cytochemical, fine structural, electrophysiologic and certain biochemical analyses of human exocrine sweat glands & possibly specimens of nasal or tracheobronchial epithelium from control & CF subjects. Alterations in these tissues maintained in explant under various experimental manipulations will be assessed along with the effect of so-called factors thought to be present in body fluids of CF patients. Efforts will continue in collaboration with Dr. W.H.J. Douglas to culture epithelial cells from sweat glands of normal and CF cubjects & investigate abnormalities in the cultured cells from the patients again employing fine structural, cytochemical, electrophysiologic, ion flux & biochemical measurements. Investigation of the presence of amiloride channels from passive Na ion transport in the human sweat gland & respiratory epithelium will be initiated. These studies, in collaboration with Dr. E.G. Cragoe of Merck Sharp & Dohme, will include radioautographic demonstration of binding of C14 and H3 labeled derivatives of this diuretic drug to specific epithelial cells. Fluorescence microscopy with various fluorescent derivatives & electron spin resonance measurements with a spin labeled derivative will be utilized for localization of amiloride channels in various epithelial cells. Freeze-fracture studies now in progress will be pursued to characterize further the nature of cell junctions between various cell types in the sweat glands and respiratory epithelium & characterize intramembranous particles in plasma membranes of these cells. Investigations of the pathogenesis of mega inclusions in cells of beige mice with a genetic defect analogous to the Chediak-Higashi syndrome will continue with emphasis on the pathogenesis of inclusions in the proximal nephron, gastric epithelium and culture fibroblasts. Development & application of cytochemical methods for localizing & characterizing complex carbohydrates of immunocytochemical methods for visualization of carbonic anhydrase & other antigens will continue.